This error happens regardless of whether we use paypal express or paypal standard.

However the system appears to work fine if they click on the 'checkout with paypal' icon rather than going through the epages checkout. Similarly if we use the 'test connection' in the payment settings then it says that the connection was successfully established.l

i've got an answer from our 2nd Level support, but the error message seems to be generated quite long time ago because they can't find it in the current logs.
But her guess is that there's something wrong with the address information (country, zip ...).

I want to repdroduce the error now, but I can see only one payment method on your site: google checkout. I can't see the "place order" button.
Shall this be correct?